Table of contents

Appendices

5.5 Semantic Attributes (

The attributes that describe the meaning of resources within the context of a link are role, arcrole, and title. The role attribute Must, May, etc. be used on extended-, simple-, locator-, and resource-type elements. The arcrole attribute Must, May, etc. be used on arc- and simple-type elements. The title attribute Must, May, etc. be used on all of these types of elements.

The value of the role or arcrole attribute Must, May, etc. be a URI reference as defined in [rfc2396], except that if the URI scheme used is allowed to have absolute and relative forms, the URI portion Must, May, etc. be absolute. The URI reference identifies some resource that describes the intended property. When no value is supplied, no particular role value is to be inferred. Disallowed URI reference characters in these attribute values Must, May, etc. be specially encoded as described in [Locator Attribute (].

The title attribute is used to describe the meaning of a link or resource in a human-readable fashion, along the same lines as the role or arcrole attribute. (However, see also [Titles for Extended Links, Locators, and Arcs (].) A value is optional; if a value is supplied, it Must, May, etc. contain a string that describes the resource. The use of this information is highly dependent on the type of processing being done. It Must, May, etc. be used, for example, to make titles available to applications used by visually impaired users, or to create a table of links, or to present help text that appears when a user lets a mouse pointer hover over a starting resource.

Following is a non-normative attribute-list declaration for role and title on an element intended to be simple-type.

<!ATTLIST simplelink
  ...
  xlink:role      CDATA           #IMPLIED
  xlink:title     CDATA           #IMPLIED
  ...>

Following is a non-normative attribute-list declaration for arcrole and title on an element intended to be arc-type.

<!ATTLIST go
  ...
  xlink:arcrole   CDATA           #IMPLIED
  xlink:title     CDATA           #IMPLIED
  ...>